A test of energy averaging in LEED: The coincidence lattice structure formed by Ag on Cu(111)

An analysis of LEED data from a structure believed to consist of a monolayer of silver on a clean copper (111) surface has been performed. Using a hard-sphere model as a guide for the surface structure, energy-averaged beam intensities from experiment have been compared with those from kinematical calculations as proposed by Tucker and Duke. Significant differences are found which are believed to be associated with multiple scattering. This casts doubt on the value of this technique for determining surface structures of strong-scattering adsorbates on metals.